Continuous process for the production of solid epoxy resins

ABSTRACT

Solid epoxy resins are produced continuously by passing a mixture of liquid epoxy resin, bisphenol and catalyst through a preheat zone, a reaction zone and a postheat zone at a positive backpressure.

United States Patent 11 1 Ramsey et al.

i i CONTINUOUS PROCESS FOR THE PRODUCTION OF SOLID EPOXY RESINS [75] lm'Qntors: David W. Ramsey. Houston; Charles H. .111} roe. Lake Jackson. both of To;

[73] Assigncc: The Dow Chemical Company,

Midland. Mich.

:2 Filed: Feh.20 l974 [2]] App]. No; 444.087

I LLS. Cl. 260/47 EP: 260/49 51] Int. Cl. .4 CUSG 30/04 1 Nov. 11.1975

[58] Field of Search 260/47 EP. (I3 Bi 5 C Primm' l;'.ru/m'nw- Mel\'in Goldstcin Ass/sum! lii'uniimr-T. Pcrtillu :i/Irn'm'). Ayn/2!, ur Firm-James G. Carter [57] ABSTRACT Solid epoxy resins are produced continuuusi} h pus ing a mixture of liquid epox rcsin hisphcnul Lllki CUI- al \sl through a prchczn zone. u reaction zone and u postheat zone at a positive huckprcssurc.

3 Claims. N0 Drawings CONTINUOUS PROCESS FOR THE PRODUCTION 0 OF SOLID EPOXY RESINS The present invention relates to a process for the CH' CH cH 0 preparation of solid epoxy resins. 5 Solid epoxy resins of the polyglycidyl ether type have usually been prepared by batch processes wherein and CH x x x x 0 Q @l ll. CP -0 (Al 0 -CHZCHCH:AO (AI 0 H. (H CH.

l X n x 0H m l. a bisphenol is reacted with an epihalohydrin in the wherein A is a divalent hydrocarbon radical having presence of a suitable catalyst and the reaction from about I to about carbon atoms, S. product subsequently dehydrohalogenated to pro- S--S, duce the epoxy resin, or 2. a liquid epoxy resin is reacted with a bisphenol in O O 0 the presence of a suitable catalyst to produce the ll l desired solid epoxy resin. T C It has now been discovered that solid epoxy resins d can be produced continuously by passing a mixture of a P epoxy m; or -O; each X is independently hydrogen, chlorine blspheno] other Suitable compound havmg or bromine, n is zero or 1 and'm has a value such that about 2 ammauc hydroxyl groups and the glycidyl ether is a liquid, i.e. pourable even though 3. a suitable catalyst for effecting reaction between 30 highly viscous, at about atmospheric pressure and the lz'epoxy groups the epoxy resm the 60C. These liquid epoxy resins have an average of hydroxyl groups of the blsphenol through a Preheat more than 1 glycidyl ether group per molecule, but not zone wherein the mixture IS heated to a temperagreater than an average of about 2 such groups per l close to but below the macho" temperature molecule. Suitable aromatic hydroxyl-containing comless g about 130C preferably between 3 pounds hereinafter referred to as dihydric phenols about 115 to abou which may be employed in the process of the present thus Preheat"? m'xture Is passed through a invention include those represented by the formulas reaction zone wherein the temperature IS controlled so as to maintain the mixture at a temperature between about l30 to about 250C, preferably about 130 to "L 0H about 160C. The mixture is then passed through a post 40 heat zone wherein the mixture is maintained at a tem- 0H perature between 130 and about 250C, preferably between about l60 and about 180C. and

The flow rate is adjusted such that the time in the reactor zone is such that the mixture has passed through X X its exotherm. The time in the post heat zone is such that the reaction is substantially complete. Iv HO A OH The process is conducted under a positive backpresn sure sufficient to eliminate surging of the reactant mixture in each zone of the process. This back pressure varies depending upon the particular reactant mixture wherein A, X and n are as defined in formula 1] above. being employed, but is usually within the range of from The molar ratio of liquid epoxy resin to aromatic hyabout 1 psig (0.07 kg/cm) to about 300 psig (21.09 droxyl-containing compound is dependent upon the kg/cm), preferably from about 10 psig (0.70 kg/cm) starting liquid epoxy resin and the epoxide equivalent to about 100 psig (7.03 kg/cm) and most preferably weight or epoxide desired in the resulting solid epoxy from about 20 psig 1.4] kg/cm) to about 40 psig resin. Those skilled in the art are familiar with the par- (2.81 kg/cm). ticular ratios of the reactants required to produce a After the solid epoxy resin has been prepared by the solid epoxy resin possessing the desired epoxide equivprocess of the present invention, it is then processed in alent weight or epoxide.

the conventional manner for ultimate use i.e. it is fil- Suitable catalysts are any catalyst which catalyzes the tered and then flaked or diluted with suitable solvents reaction between a vicinal epoxy group and a phenolic to prepare solution resins useful as coatings and the hydroxyl group. Such catalysts include, for example, like. organic ammonium compounds such as benzyltrime- Suitable liquid epoxy resins which may be suitably thylammonium chloride, organic phosphines such as employed in the process of the present invention intriphenylphosphine and organic phosphonium comclude the glycidyl ethers of aromatic dihydroxyl-con' pounds such as ethyltriphenyl phosphonium iodide, taining compounds such as those represented by the ethyl triphenyl phosphonium acetate.acetic acid comformulas plex. Such catalysts are well known in the art and are disclosed in Handbook of Epoxy Resins by Lee and Neville, McGraw Hill Book Co., 1967, U.S. Pat. No. 3,341,580; U.S. Pat. No. 3,477,990; U.S. Pat. No. 3,547,881; and Canadian Pat. No. 893,191.

EXAMPLE 1 A liquid diglycidyl ether of bisphenol-A (D.E.R. 331) having an epoxide equivalent weight of 182-190 and bisphenol-A were fed into a Kenics static mixer. The liquid epoxy resin was fed at a temperature of 80C at a rate of 228 lbs/hour (103.42 kg) and the bisphenol-A was fed at 160C at a rate of 72 lbs. (32.66 kg) per hour. This mixture was then fed into an agitated continuous mixer where it was admixed with a 25% methanol solution of ethyltriphenyl phosphonium acetate.acetic acid complex at a rate of 38 grams of solution per hour. The resultant catalyzed mixture was then fed into a ft. long, 2 inch 1D jacketed preheat zone wherein the mixture was heated to a temperature of 120C. The thus heated mixture was then fed into a 150 ft. long, 2 inch l.D. jacketed reaction zone wherein the temperature was maintained at 150-160C. The resultant partially reacted product which had passed through its exotherm period was then fed into a jacketed 170 ft. long 2 inch 1D post-heat zone wherein the mixture was maintained at a temperature of 160180C wherein the reaction was completed and subsequently flaked. The above system was maintained at a backpressure of 20 psig 1.41 kg/cm) so as to prevent surging. The resultant solid product had a epoxide of 8.38 (EEW 518). a viscosity at 150C of 470 centistokes and a phenolic hydroxyl content of 0.034%.

EXAMPLE 2 The process of Example 1 was repeated employing the following reactants and catalyst.

221 lbs (100.25 kg)/hr of D.E.R. 331

87 lbs (39.46 kg)/hr of bisphenol-A 38 g/hour of a methanol solution of ethyltriphenyl phosphonium acetate.acetic acid catalyst solutron.

The resultant product was characterized as follows:

% epoxide 6.35 (EEW 677) viscosity at 150C 1524 centistokes Phenolic OH 0.012

EXAMPLE 3 The process of Example 1 was repeated employing the following reactants and catalyst.

213 lbs (96.62 kg)/hr of D.E.R. 331

87 lbs (39.46 kgl/hr of bisphenol-A 4 50 g/hr of a 25% methanol solution of ethyltriphenyl phosphonium acetate.acetic acid catalyst solution. The resultant product was characterized as follows: epoxide 5.6 (EEW 767) viscosity at 150C 3166 centistokes phenolic OH 0.014.

EXAMPLE 4 The process of Example 1 was repeated employing the following reactants and catalyst.

210 lbs (95.26 kg)/hr of D.E.R. 331

lbs (40.82 kg)/hr of bisphenol-A 50 g/hr of a 25% methanol solution of ethyltriphenyl phosphonium acetate.acetic acid complex catalyst.

The resultant product had the following characteristics:

% epoxide 4.89 (EEW 879) Viscosity at 150C 8347 centistokes phenolic OH 0.069.

We claim:

1. A process for the continuous production of solid epoxy resins which comprises passing a reaction mixture comprising a liquid aromatic epoxy resin containing 62-epoxy groups, a dihydric phenol and a catalyst for effecting a reaction between said liquid epoxy resin and dihydric phenol through first, a preheat zone wherein the reaction mixture is heated to a temperature below the reaction temperature of said mixture;

second, a reaction zone wherein the reaction mixture is maintained at a temperature between about 130 to about 250C; and

third, a post-heat zone wherein the temperature is maintained at a temperature between about 130 to about 250C, while maintaining a positive backpressure in each of said first, second and third zones; and subsequently recovering the resultant solid epoxy resin.

2. The process of claim 1 wherein the temperature of the reaction mixture in said preheat zone is from about 1 15 to about C, the temperature of the reaction mixture in said reactions zone is from about to about C and the temperature of the reaction mixture in said post-heat zone is from about 160 to about C and the backpressure is from about 20 to about 40 psig (1.41 to 2.81 kg/cm).

3. The process of claim 2 wherein said liquid epoxy resin is a diglycidyl ether of bisphenol-A and said dihydric phenol is bisphenol-A.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,919,169 DATED 1 Nov. 11, 1975 INVENTOR(S) David W. Ramsey, et al.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 1 and Col. 2, formula, between brackets please add a bond from "CH" to "OH".

Col. 4, line 25, please delete "62-" and add -l,2

Col. 4, line 43, change "reactions" to -reaction.

Signed and Sealed this T n 4n Bar of we ty rs y September 1976 A nest:

RUTH.C. MAnSON C. MARSHALL DANN Arresrrng ()fjrcer Commissioner uflarems and Trademarks 

1. A PROCESS FOR THE CONTINUOUS PRODUCTION OF SOLID EPOXY RESINS WHICH COMPRISES PASSING A REACTION MIXTURE COMPRISING A LIQUID AROMATIC EPOXY RESIN CONTAINING 62-EPOXY GROUPS, A DIHYDRIC PHENOL AND A CATALYST FOR EFFECTING A REACTION BETWEEN SAID LIQUID EPOXY RESIN AND DIHYDRIC PHENOL THROUGH FIRST, A PREHEAT ZONE WHEREN THE REACTION MIXTURE IS HEATED TO A TEMPERATURE BELOW THE REACTION TEMPERATURE OF SAID MIXTURE, SECOND, A REACTION ZONE WHEREIN THE REACTION MIXTURE IS MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 130* TO BOUT 250*C, AND THIRD, A POST-HEAT ZONE WHEREIN THE TEMPERATUREIS MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 130* TO ABOUT 250*C, WHILE MAINTAINING A POSITIVE BACKPRESSURE IN EACH OF SAID FIRST, SECOND AND THIRD ZONES, AND SUBSEQUENTLY RECOVERING THE RESULTANT SOLID EPOXY RESIN.
 2. The process of claim 1 wherein the temperature of the reaction mixture in said preheat zone is from about 115* to about 125*C, the temperature of the reaction mixture in said reactions zone is from about 130* to about 160*C and the temperature of the reaction mixture in said post-heat zone is from about 160* to about 180*C and the backpressure is from about 20 to about 40 psig (1.41 to 2.81 kg/cm2).
 3. The process of claim 2 wherein said liquid epoxy resin is a diglycidyl ether of bisphenol-A and said dihydric phenol is bisphenol-A. 